This is called the base 10 representation of the given numbers or the generalised form of the number.

Consider, for example 136. We can write this in the generalised form as:

136 = (1 x100) + (3 x 10) + (6 x 1)

We see that, 6 is associated with 1; 3 is associated with 10; and 1 is associated with 100. This is the reason, 6 is called the digit in the unit’s place; 3 is the digit in the ten’s place and 1 is the digit in the hundred’s place.